Rocker-swivel device



United States Patent {72} lnventor Samuel E. Gordin Fort Smith, Ark.

[2]] Appl. No. 696,364

[22] Filed Jan. 8, 1968 [45] Patented Dec. 15, 1970 [73] Assignee Hickory Springs Manufacturing Co., Inc.

Hickory, N.C.

a corporation of North Carolina [54] ROCKER-SWIVEL DEVICE 6 Claims, 4 Drawing Figs.

[52] US. Cl 248/385, 297/263 [51] Int. Cl. A47c 3/02 [50] Field of Search 248/385,

Primary Examiner-Francis K. Zugel ArtorneyChanning L. Richards, Dalbert U. Shefte and Francis M. Pinckney ABSTRACT: A rocker swivel device for incorporation in a chair structure to support the seat portion thereof for both rocking and swiveling action. The device has a bottom plate member on which a middle plate member is supported through a circular ball race assembly for swiveling movement about a centrally disposed vertical swivel axis at which the bottom and middle plate members are connected. The middle plate member has upstanding side flanges that are connected at a centrally disposed horizontal rocking axis to depending side flanges of a top plate member for rocking movement of the top plate member, with the top plate member side flanges disposed inwardly of the middle plate member side flanges for balance and to prevent lateral displacement in the event of x failure of the rocking pivot connection. The top and middle plate members are formed with front and rear spring-retaining pockets disposed compactly in the corner areas thereof outboard of and closely adjacent the circular ball race, and are further formed with interior spring-retaining pockets inboard of the circular ball race. An oppositely wound pair of vertically disposed front coil springs are secured in the front spring-retaining pockets to control in both compression and tension the rocking action of the top plate member, and a pair of rear coil springs may be secured in the rear spring-retaining pockets or an interior coil spring may be secured in the interior spring-retaining pockets or both or neither to provide a desired compression and tension spring action to suit particular chair structure characteristics, thus providing a versatile device that can be readily modified to provide desired rocking action control.

PATENTED mm 5 mm 3; 547', 393

SHEET 1 BF 2 INVENTOR. sAmuea. a. scream BY EQRLMMQ, I I9 2 M S AT'ro NEYS PATENTEDUHZI SIHYU 3547.393

SHEET 2 UF 2 Z0 6 7a 36 62 786 4 i j 0 1 i I 44 INVENTOR.

SAMUEL E. GORDIN ATTORN Y5 ROCKER-SWIVEL DEVICE BACKGROUND OF THE INVENTION The present invention relates to rocker-swivel devices used in chair structures of various types toprovide both rocking and swiveling of a chair seat portion. Devices of this type generally utilize vertically disposed coil springs to control the rocking action with the springs arranged compactly for effective spring utilization and long-wear life and arranged in a balanced manner to provide a balanced rocking action of the chair structure.

A typical example of an effective prior art device of this type is disclosed in Underdown U.S. Pat. No. 3,190,693, issued June 22, 1965, which shows a rocker-swivel device having a top place member rockably mounted on a middle plate member by abutting arcuate runners formed on side flanges of the top and middle plate members with pairs of coil springs attached at each side of and extending between the top and middle plate members. This device provides excellent rocking action in a compact arrangement having'a long-wear life. It is, however, comparatively expensive to manufacture and cannot be adapted to varying spring characteristics, except during original manufacture. I

Another prior art device of the general type of the present invention is disclosed in Hunt and McMahan US. Pat. No. 3,263,955, issued Aug. 2, I966, which shows a rocker-swivel device having a top plate member with depending side flanges pivotally secured by pivot rivets to upstanding side flanges of a middle plate member at a horizontal rocking axis offset a substantial distance rearwardly from a central vertical swivel axis. A pair of coil springs are mounted between the top and middle plate members at the front of the device to control rocking by compression and tension, and a third coil spring is biased between the top and middle plate members rearward of the rocking axis to act in compression only to cushion rearward rocking. As the rocking axis is rearwardly offset the extent of expansion and contraction of the front coil springs is substantial, and, therefore, reduces the effective utilization of the springs and reduces the wear life thereof. The rearward offset of the rocking axis also creates imbalance in relation to the central swivel axis and restricts any possible utilization of rear springs in the limited area rearward of, the rocking axis. For these reasons, the device of this prior art patent is not effectively balanced and is not readily adaptable to provide a wide range of rocking action characteristics. Further, in the device of this prior art patent one side flange of the top plate member is outside the side flange of the middle plate member and the other top plate member side flange is inside the other middle plate side flange with the result that not only does this produce imbalance, but in the event the rocker pivot rivets fail the top plate member may be displaced laterally causing the chair seat portion and its occupant to fall to the side.

What the prior art has lacked and what the present invention provides is a rocker-swivel device-that combines effective and long-wearing spring utilization in a balanced and compact assembly having a wide versatility that permits ready modification to provide desired spring characteristics by simply varying the size and number of springs in a standard assembled device without having to assemble separate complete devices for each different chair structure.

SUMMARY OF THE INVENTION The advantages of the present invention are obtained with a rocker-swivel device that includes a bottom plate member that supports, through a circular ball race, a middle plate member for swiveling about a centrally disposed vertical swivel axis, with the middle plate member supporting a top plate member for rocking movement at a centrally disposed horizontal pivot axis generally coplanar with the swivel axis for balance and located at upstanding side flanges of the middle plate member and depending side flanges of the top plate member. The top and middle plate members are generally coextensive and have front and rear edges closely adjacent the extremities of the ball race with a pair of front spring-retaining pockets and a pair of rear spring-retaining pockets formed in each of the top and middle plate members and extending inwardly from the front and rear edges in the corner areas thereof outboard of the ball race with the pockets of each pair being spaced equally from opposite plate member side flanges, thereby providing a balanced compact mounting location for springs as close to the horizontal pivot axis as possible without interference with the ball race for enhanced spring utilization. A pair of vertically disposed front coil springs extend between the top and middle plate members and are secured in the pairs of front spring-retaining pockets for compression and tension spring action to control the rocking action of the top plate member. The provision of the rear spring-retaining pockets renders the device versatile in that identical components, except for springs, can be assembled into devices that may be readily adapted to provide spring characteristics over a wide range simply by adding or omitting the rear coil springs or utilizing springs having different spring characteristics.

In the preferred embodiment of the present invention, the pair of front coil springs are oppositely wound to apply balancing spring forces to the top and middle plate members during rocking movement, with the pair of rear springs, when used, being also oppositely wound for the same purpose. The rear spring-retaining pockets in the preferred embodiment are smaller than the front spring-retaining pockets and have their centers closer to the side flanges and to the horizontal pivot axis for compactness and enhanced utilization of rear coil springs, which are normally of .smaller size than the front springs to provide a desired balanced rocking action in com.- bination with the front springs.

For further versatility and balancing, the top and middle plate members of the preferred embodiment have interior spring-retaining pockets formed therein and spaced inwardly of the ball race on the longitudinal centerline of the device at a rearward spacing from the swivel axis for balanced and effective utilization of a vertically disposed interior coil spring that may, if desired to obtain particular rocking spring action, be secured in the interior spring-retaining pockets for compression and tension spring action to control rocking of the top plate member in combination with the other springs.

In addition, in the preferred embodiment the side flanges of the top plate member are both disposed inwardly of the side flanges of the middle plate member for balance and for prevention of lateral displacement of the top plate member and an attached chair seat portion in the event of failure of the horizontal pivot connection.

Thus, the present invention provides a compact rockerswivel device that is arranged for balanced action and effective spring utilization, that is versatile which respect to the range of spring characteristics that can be provided, and that safely prevents separation of the components in the event of failure of the rocking pivot connection.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rocker-swivel device according to the preferred embodiment of the present invention; FIG. 2 is a plan view of the rocker-swivel device of FIG. 1;

FIG. 3 is a front elevational view of the rocker-swivel device of FIG. 1 as viewed from the opposite end thereof; and

FIG. 4 is a vertical sectional view of the rocker-swivel device of FIG. 1, taken along line 4-4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT axis forming hole 16, and an upwardly facing circular ball race 18 centered at the center swivel axis forming hole 16.

A horizontally disposed middle plate member 20 is positioned above the bottom plate member 12 in face-to-face relation thereto and has a downwardly facing ball race 22 superjacent the bottom plate member ball race 18 and cooperating therewith to retain a plurality of ball elements 24 in the ball races for swiveling support of the middle plate member 20 on the bottom plate member 12, to which the middle plate member 20 is connected for swiveling by means in the fonn of a center staking rivet 26 passing through the aforementioned bottom plate member center hole 16 and a middle plate member center hole 28 at a centrally disposed vertical swivel axis 30.

The middle plate member 20 is generally rectangular in shape and has opposed upstanding side flanges 32 at which opposed depending side flanges 34 of a top plate member 36 are disposed in face-to-face relation thereto and are pivotally connected thereto by means in the form of a pair of aligned rivets 38 at a centrally disposed horizontal pivot axis 40 that is substantially coplanar with the vertical swivel axis 30 for balanced rocking movement of the top plate member 36 with respect to the middle plate member 20. To minimize friction and noise during rocking, plastic washers 42 are seated on the rivets 38 outwardly of the middle plate member side flanges 32 and between the top and middle plate member side flanges 34 and 32.

As seen in the drawings, the middle plate member side flanges 32 are disposed outwardly of the top plate member side flanges 34 for balance and for prevention of lateral displacement of the top plate member 36 and chair seat portion (not shown), that is to be attached thereto at the laterally projecting ears 44, in the event of failure of the pivot rivets 38 during use of the chair, thereby minimizing structural damage and physical harm to the chair occupant.

The middle plate member 20 has front and rear edges 46 and 48, respectively, closely adjacent the front and rear extremities 50 and 52, respectively, of the ball race 22 for compactness. At the front edge 46 the middle plate member 20 is formed with a pair of front spring-retaining pockets 54 that are struck upwardly and extend inwardly from the front edge 46 in the front corner areas 56 outboard of the ball race 22 at equal spacings from the opposite bottom plate member side flanges 32 for balanced disposition of springs therein as close to the horizontal pivot axis 40 as possible without interfering with the ball race 22. At the rear edge 48 the middle plate member 20 is formed with a similar pair of rear spring-retaining pockets 58 struck upwardly and extending inwardly from the rear edge 48 in the rear corner areas 60 outboard of the ball race 22 at equal spacings from the opposite bottom plate member side flanges 32 for balanced disposition of springs therein. As smaller diameter springs are used at the rear than at the front to obtain proper balanced rocker action, the rear spring-retaining pockets 58 are smaller than the from springretaining pockets 54 and they have their centers disposed closer to the side flanges 32 and to the horizontal pivot axis 40 than the front spring-retaining pockets 54 without interfering with the ball race 22, which results in compactness of the rear corner areas 60 and enhanced spring utilization and wear life.

The top plate member 36 is normally horizontally disposed and is generally rectangular in shape, being substantially coextensive with the middle plate member 20 and having front and rear edges 62 and 64, respectively, downwardly struck front and rear spring-retaining pockets 66 and 68, respectively, disposed in front and rear corner areas 70 and 72, respectively, all of which are vertically aligned with the corresponding portions of the middle plate member 20.

The middle plate member 20 is further formed with an upwardly struck interior spring-retaining pocket 74 spaced inwardly of the ball race 22 on the longitudinal centerline of the middle plate member 20 at a rearward spacing from the vertical swivel axis 30 for balanced mounting of an interior spring inboard of the ball race 22, and the top plate member 36 is similarly formed with a downwardly struck interior springretaining pocket 76 in vertical alignment with the middle plate member interior spring-retaining pocket 74. As a result of the striking of these interior spring-retaining pockets 74 and 76 from their respective plate members 20 and 36, respectively, openings 78 and 80, respectively, are formed at the pockets for insertion of spring coils therein.

Mounted at the front of the device 10 is a pair of vertically disposed front coil springs 82 that extend between the top and middle plate members 20 and 36 and have their uppermost coils 84 seated in the top plate member front spring-retaining pockets 66 and retained therein by inwardly extending tabs 86 upwardly struck from the centers of the pockets. The lowermost spring coils 88 are similarly seated in the middle plate member front spring-retaining pockets 54 and retained therein by inwardly extending tabs 90 downwardly struck from the centers of the pockets. These front coil springs 82 act in both compression and tension to control the rocking action of the top plate member 36 in both forward and rearward rocking thereof, for which purpose they are partially open when the top plate member 36 is in a neutral horizontal position. Further, these front coil springs 82 are oppositely wound to apply balanced spring forces to the top and middle plates 20 and 36 and to provide longer wear life to the springs than when commonly would springs are used.

For lightweight rocking action, the front coil springs 82 may be sufficient in themselves to provide adequate control of rocking so that no other springs are needed. For heavier rocking action, either a pair of smaller rear coil springs 92 or an interior coil spring 94 or both may be included, and as spring-retaining pockets are provided for these additional springs it is an easy matter to provide the desired spring combination for a particular use from a common stock of identical devices without having to fabricate separate components to obtain devices having different springcharacteristics. Thus, the interior coil spring 94 and the rear coil springs 92 together comprise coil spring means selectively secured in either or both the interior spring-retaining pockets 74 and 76 or the pairs of rear spring-retaining pockets 58 and 68 and extending between the middle and top plate members 20 and 36, respectively, to provide, in combination with the front coil springs 82, versatile rocking action control to suit various chair structure requirements.

ln the embodiment illustrated, both rear coil springs 92 and an interior coil spring 94 are included. The rear coil springs 92 are vertically disposed and extend between the top and middle plate members 20 and 36 and have their uppermost coils 96 seated in the top plate member rear spring-retaining pockets 68 and retained therein by inwardly extending tabs 98 upwardly struck from the centers of the pockets, with their lowermost coils 100 similarly seated in the middle plate member rear spring-retaining pockets 58 and retained therein by inwardly extending tabs 102 downwardly struck from the centers of the pockets. The interior coil spring 94 is vertically disposed and extends between the top and middle plate members 20 and 36 and has its uppermost coil 104 seated in the top plate member interior spring-retaining pocket 76 and retained therein by an upwardly extending tab 106 struck from the center of the pocket, with its lowermost coil 108 similarly seated in the middle plate member interior spring-retaining pocket 74 and retained therein by a downwardly extending tab 110 struck from the center of the pocket.

The rear coil springs 92 are oppositely wound to provide the same balanced action and long-wear life as aforementioned in regard to the oppositely wound front coil springs 82.

The rear coil springs 92 and interior coil spring 94 act in both compression and tension to control rocking action in combination with the front coil springs 82, for which purpose they are partially open whenthe top plate member 36. is in a neutral position. However, the primary function of these rear coil springs 92, and particularly the interior coil spring94, is to act in compression to control rearward rocking and to. cushion rearward rocking as the rocking approaches its rearward limit.

To provide desirable balance when the top plate member 36 is in its neutral position, all of the springs 82, 92 and 94 are preloaded in tension when they are assembled in the device with the top plate member 36 in its neutral horizontal disposition.

The diagonal ribs 112 and lateral ribs 114 shown formed in the top plate member 36 are provided to strengthen the otherwise flat member.

The preferred embodiment described in detail hereinabove and illustrated in the accompanying drawings is a representative example of an embodiment of the present invention, which is not intended to be limited to this embodiment or otherwise, except as defined in the appended claims.

lclaim:

l. A rocker-swivel device for incorporation in a chair structure to support the seat portion thereof for both rocking and swiveling action, said device comprising a bottom plate member, a middle plate member disposed above said bottom plate member in face-to-face relation thereto, means connecting said bottom plate member and said middle plate-member at a centrally disposed vertical swivel axis for swiveling movement of said middle plate member about said swivel axis, said bottom plate member having an upwardly facing circular ball race formed therein and centered at said swivel axis, said middle plate member having a downwardly facing circular ball race superjacent said bottom plate member ball race, a plurality of ball elements disposed in said ball races for swiveling support of said middle plate member on said bottom plate member, said middle plate member having opposed upstanding side flanges, a top plate member disposed coextensively above said middle plate member for support of a chair seat portion thereon and having opposed depending side flanges extending into face-to-face relation to said middle plate member side flanges, means pivotally connecting said top plate member side flanges to said middle plate member side flanges at a centrally disposed horizontal pivot axis substantially coplanar with said vertical swivel axis for rocking movement support of said top plate member on said middle plate member, said middle plate member having front and real edges closely adjacent the extremities of said ball race and having a pair of front and a pair of rear spring-retaining pockets formed therein and extending inwardly from said edges in the corner areas of said middle plate member outboard of said ball race with said front spring-retaining pockets being equally spaced from opposite middle plate member side flanges and said rear spring-retaining pockets being equally spaced from opposite middle plate member side flanges for balanced mounting of front and rear coil springs, said top plate member having from and rear edges and front and rear spring-retaining pockets vertically aligned with said middle plate front and rear edges and front and rear spring-retaining pockets, said middle and top plate members each having an interior spring retaining pocket formed therein and spaced inwardly of said ball race on the longitudinal centerline of said middle and top plate members at a rearward spacing from said swivel axis and in'vertical alignment with each other, a pair of vertically disposed front coil springs extending between said top and middle plate members and secured in said front spring-retaining pockets for compression and tension spring action to control the rocking action of said top plate member, and coil spring means selectively securedin either or both said interior spring-retaining pockets or said pairs of rear springretaining pockets and extending between said middle and top plate members to provide, in combination with said front coil springs, versatile rocking action control to suit various chair structure requirements.

2. A rocker-swivel device according to claim 1 and characterized further in that said coil spring means includes a pair of vertically disposed rear coil springs extending between said top and middle plate members and secured in said rear springretaining pockets for compression and tension spring action to control the rocking action of said top plate member in combination with said pair of front coil springs.

3. A rocker-swivel device according to claim 2 and characterized further in that said front coil springs are oppositely wound and said rear coil springs are oppositely wound to apply balanced spring forces to said top and middle plate members during rocking movement.

4. A rocker-swivel device according to claim 1 and characterized further in that said rear spring retaining pockets are smaller than said front spring retaining pockets and have their centers disposed closer to said side flanges and to said horizontal pivot axis than said front spring retaining pockets for compactness of said rear corner areas and enhanced spring utilization.

5. A rocker-swivel device according to claim 4 and characterized further in that said coil spring means includes a pair of vertically disposed rear coil springs of small diameter than said front coil springs and secured in said rear spring retaining pockets for extension between said top and middle plate members to control by compression and tension spring action the rocking movement of said top plate member in combination with said pair of front coil springs.

6. A rockenswivel device according to claim 1 and characterized further in that said middle plate member sideflanges are disposed outwardly of said top plate member side flanges for balance and to prevent lateral displacement of said top plate member and chair seat portion in the event of failure of said pivotally connecting means. 

